In 2014, a record-breaking volcanic eruption spewed lava and ash over Iceland’s Highlands for nearly six months, leaving behind the largest caldera formation ever observed.

The Bardarbunga eruption was the strongest of its kind in Europe in more than 240 years, and released two cubic kilometers of volcanic material.

Now, researchers from the GFZ German Research Centre for Geosciences have studied the event in new detail, using satellite images, seismological and geochemical data, GPS data, and modelling to document the eruption.

Scroll down for video

In 2014, a record-breaking volcanic eruption spewed lava and ash over Iceland’s Highlands for nearly six months, leaving behind the largest caldera formation ever observed. The Bardarbunga eruption was the strongest of its kind in Europe in more than 240 years

A caldera is a kettle-shaped structure formed by the collapse of underground magma reservoirs during an eruption.

Share this article

The researchers say the subsidence was spurred by the influx of underground magma, 12 kilometers below the surface.

The magma flow ran for 45 kilometers before erupting northeast of the volcano.

As this happened, there were 77 earthquakes, of magnitudes larger than M5.

The researchers say the subsidence was spurred by the intrusion of underground magma, 12 kilometers below the surface

‘With an area of 110 square kilometers, this is the largest caldera collapse ever monitored,’ says Dr Eoghan Holohan, who led the modelling part of the study.

‘The results provide the clearest picture yet of the onset and evolution of this enigmatic geological process.’

The new analyses revealed how the subsistence bowl slowly formed over six months, growing to eight by eleven kilometers wide, and up to 65 meters deep.

THE RECORD-BREAKING BARDARBUNGA ERUPTION

Iceland’s Met Office issued a 'red alert' at the end of August 2014 after the Bardarbunga volcano, which lies underneath the Vatnajökull glacier, experienced a 'small' eruption.

The aviation threat was reduced months later, though scientists at the time warned there was still gas contamination in the area around the eruption site.

Bardarbunga is a large central volcano lying underneath Iceland's Vatnajokull glacier, in the centre of the country.

The aerial photo from September 14, 2014 shows the Bardarbunga volcano spewing lava and smoke in southeast Iceland

It contains a 2,296ft-deep (700 metre) caldera, hidden beneath ice, covered in extensive flank fissures, from where the majority eruptions take place.

The most recent eruption began in August 2014, and lasted until February 2015.

The Veidivötn fissure extends for over 62 miles (100km) to the south west, almost reaching Torfajökull volcano, while the Trollagigar fissure extends 31 (50km) to the north east, towards the Askja volcano.

Bardarbunga is a large central volcano lying underneath Iceland's Vatnajokull glacier, in the centre of the country

‘The typical structure of seismic waves in volcanic eruptions can be used to infer the type of deformation directly above the magmatic chamber,’ says Dr Sebastian Heimann, who investigated the mechanisms underlying the collapse using seismological methods.

The researchers say this indicates the subsistence was controlled by ‘steeply-dipping ring faults.’

‘Interestingly, the eruption site and the magma chamber were coupled hydraulically over 45 kilometers,’ Dr Thomas Walter, who says the effect is something like a hose pipe level.

The tremors and shocks of the eruption spread to the magma chamber at the other end.

The magma flow ran for 45 kilometers before erupting northeast of the volcano. As this happened, there were 77 earthquakes, of magnitudes larger than M5

Iceland’s Met Office issued a 'red alert' at the end of August 2014 after the Bardarbunga volcano, which lies underneath the Vatnajökull glacier, experienced a 'small' eruption. This was later lifted in February

This new analysis helps to provide deeper insight on caldera formation, which can be tied to eruptions far more catastrophic than that observed in Iceland.

While the event was enormous, the researchers say it could have been worse under different conditions, as the chamber sits beneath the Vatnajokull, Europe’s largest glacier.

‘The event was a blessing in disguise as the eruption could have happened directly beneath the ice,’ Dr Walter says.

‘In that case, we’d have had a water vapour explosion with a volcanic ash cloud even bigger and longer lasting than the one that followed the eruption of Eyjafjallajokull in 2010.’

Advertisement

Share or comment on this article:

Icelandic megaeruption that lasted SIX MONTHS caused by record breaking 'kettle' of magma